1. Field of the Invention
This invention generally relates to semiconductor manufacturing equipment and, more particularly, to an improved method for rapid thermal processing of a semiconductor wafer.
2. Related Art
In the semiconductor manufacturing industry, depending upon the particular process, a semiconductor wafer may be treated at temperatures of from about 100° C. to about 1300° C., under controlled conditions, in rather sophisticated furnaces. Commonly, these furnaces are horizontal or vertical type furnaces, which use various energy sources to heat the wafer, including radiant heaters, arc lamps, and tungsten-halogen lamps. As shown in FIG. 1, a typical horizontal or vertical type furnace requires a time t1 for ramping up to a particular process temperature to process the wafers. The ramp up rate for a typical furnace is usually between 5° C./min to about 15° C./min, which makes time t1 typically on the order of about 1 hour. A time t2 is required for cooling of the wafers, which is generally on the order of about 2 hours. Long processing times are typically unacceptable in advanced semiconductor device manufacturing because of dopant redistribution, excessive costs, excessive exposure to temperature, and high power requirements.
In order to continue to make advancements in the development of semiconductor devices, especially semiconductor devices of decreased dimensions, new processing and manufacturing techniques have been developed. One such processing technique is know as Rapid Thermal Processing (RTP), which reduces the amount of time that a semiconductor device is exposed to high temperatures during processing. The rapid thermal processing technique, typically includes raising the temperature of the wafer and holding it at that temperature for a time long enough to successfully perform a fabrication process, and avoid such problems as unwanted dopant diffusion that would otherwise occur at the high processing temperatures.